Friday, October 27, 2023 at 12:15 pm

JILA Foothills Room

Kenny, CU Boulder

"Studying the Solar Corona and Solar Wind with the Parker Solar Probe"

Abstract:

The Wide-field Imager for Parker Solar Probe (WISPR) captures white- light images of the inner heliosphere as Parker Solar Probe (PSP) rushes through the plasma. Near perihelion, the spacecraft’s rapid speeds and proximity to linear density structures in the corona enable a unique opportunity to extract locations of such features and large- scale structure, near the track of the spacecraft itself. This tomographic reconstruction method relies on known perspective changes due to the rapid trajectory of PSP through the solar corona. To produce the inversions we neglect local proper motions and model the apparent kinematics of stationary features, from WISPR's point of view. We produce a family of analytic functions which serve as a partial basis for the vector space of WISPR image sequences; a change- of-basis operation yields a “tomogram,” which constrains feature location with respect to the orbital track. For initial analyses, this tomogram corresponds to the ribbon of material whose length runs along the track of the spacecraft (over a selected window of time) and whose width runs perpendicular to that track (locally horizontal). Having applied our tomographic tool to a synthetic image sequence, using two different geometric approximations of the spacecraft’s trajectory, we found that our reconstructed positions did not match known positions of the features in the image sequence. We then built our own synthetic dataset to continue rigorously testing the tomography method and used this synthetic image-rendering code to generate synthetic basis elements, as opposed to the previous analytic basis elements. Our latest inversion efforts, using this synthetic partial basis, have produced promising results which we will soon begin applying to real WISPR data. I will describe the methodology and successive results of our reconstructions heretofore, as well as the implications this work has for understanding basic science of the corona and contextualizing other PSP measurements.

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